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| Research article summary (published 10 Apr 2007): |
Explicit contextual information selectively contributes to predictive switching of internal models.
Full Abstract
Many evidences suggest that the central nervous system (CNS) acquires and switches internal models for adaptive control in various environments. However, little is known about the neural mechanisms responsible for the switching. A recent computational model for simultaneous learning and switching of internal models proposes two separate switching mechanisms: a predictive mechanism purely based on contextual information and a postdictive mechanism based on the difference between actual and predicted sensorimotor feedbacks. This model can switch internal models solely based on contextual information in a predictive fashion immediately after alteration of the environment. Here we show that when subjects simultaneously adapted to alternating blocks of opposing visuomotor rotations, explicit contextual information about the rotations improved the initial performance at block alternations and asymptotic levels of performance within each block but not readaptation speeds. Our simulations using separate switching mechanisms duplicated these effects of contextual information on subject performance and suggest that improvement of initial performance was caused by improved accuracy of the predictive switch while adaptation speed corresponds to a switch dependent on sensorimotor feedback. Simulations also suggested that a slow change in output signals from the switching mechanisms causes contamination of motor commands from an internal model used in the previous context (anterograde interference) and partial destruction of internal models (retrograde interference). Explicit contextual information prevents destruction and assists memory retention by improving the changes in output signals. Thus, the asymptotic levels of performance improved.
Author information
Author/s: Imamizu, Hiroshi (H); Sugimoto, Norikazu (N); Osu, Rieko (R); Tsutsui, Kiyoka (K); Sugiyama, Kouichi (K); Wada, Yasuhiro (Y); Kawato, Mitsuo (M);
Affiliation: Department of Cognitive Neuroscience, ATR Computational Neuroscience Laboratories, 2-2-2, Hikaridai, Keihanna Science City, Kyoto 6190288, Japan. imamizu(-atsign-)atr.jp
Journal and publication information
Publication Type: Journal Article
Journal: Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale (Exp Brain Res), published in Germany. (Language: eng)
Reference: 2007-Aug; vol 181 (issue 3) : pp 395-408
Dates: Created 2007/07/19; Completed 2008/01/11; Revised 2008/02/15;
PMID: 17437093, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )
Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.
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